From ef3ff3eee48d88ce35b87409c0d96a12f75f044b Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 11 Oct 2007 21:28:05 +0000 Subject: [PATCH] Ensure that the result of evaluating a function during constant-expression simplification gets detoasted before it is incorporated into a Const node. Otherwise, if an immutable function were to return a TOAST pointer (an unlikely case, but it can be made to happen), we would end up with a plan that depends on the continued existence of the out-of-line toast datum. --- src/backend/optimizer/util/clauses.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 207eeb7bf2c..1a06839e734 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.223.2.3 2007/05/01 18:54:01 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.223.2.4 2007/10/11 21:28:05 tgl Exp $ * * HISTORY * AUTHOR DATE MAJOR EVENT @@ -3040,9 +3040,20 @@ evaluate_expr(Expr *expr, Oid result_type) /* Get back to outer memory context */ MemoryContextSwitchTo(oldcontext); - /* Must copy result out of sub-context used by expression eval */ + /* + * Must copy result out of sub-context used by expression eval. + * + * Also, if it's varlena, forcibly detoast it. This protects us against + * storing TOAST pointers into plans that might outlive the referenced + * data. + */ if (!const_is_null) - const_val = datumCopy(const_val, resultTypByVal, resultTypLen); + { + if (resultTypLen == -1) + const_val = PointerGetDatum(PG_DETOAST_DATUM_COPY(const_val)); + else + const_val = datumCopy(const_val, resultTypByVal, resultTypLen); + } /* Release all the junk we just created */ FreeExecutorState(estate);